Tag: PET scan

Use Of Total-Body Pet Imaging To Identify Deep-Tissue Sars-Cov-2 Viral Reservoirs And T Cell Responses In Patients With Long Covid

Project Summary:

This study is the first in the world to use advanced imaging technologies to identify deep tissue SARS-CoV-2 reservoirs and T cell activity in LongCovid study participants. Specifically the team will use longitudinal ImmunoPET-CT imaging of radiolabeled SARS-CoV-2-specific monoclonal antibodies (mAbs) to identify SARS-CoV-2 tissue reservoirs in individuals with Long COVID. The project team is also using ImmunoPET-CT imaging to identify the spatial and temporal dynamics of tissue-based T cell activity in Long COVID study participants.

Tissue biopsy samples from the lymph node and gut will also be collected from Long COVID study participants undergoing imaging. These tissue samples will be analyzed for SARS-CoV-2 RNA, spike, and nucleocapsid proteins, other chronic viruses (e.g., Epstein-Barr virus and cytomegalovirus), and cellular immune responses. Data collected on the tissue samples will be correlated with the imaging data, so that potential viral reservoirs and T cell activity in study participants can be validated by overlapping methods.

Read full article HERE.

Effect of Post-COVID-19 on Brain Volume and Glucose Metabolism: Influence of Time Since Infection and Fatigue Status

Abstract:

Post-COVID-19 syndrome (PCS) fatigue is typically most severe <6 months post-infection. Combining magnetic resonance imaging (MRI) and positron emission tomography (PET) imaging with the glucose analog [18F]-Fluorodeoxyglucose (FDG) provides a comprehensive overview of the effects of PCS on regional brain volumes and metabolism, respectively. The primary purpose of this exploratory study was to investigate differences in MRI/PET outcomes between people < 6 months (N = 18, 11 female) and > 6 months (N = 15, 6 female) after COVID-19.
The secondary purpose was to assess if any differences in MRI/PET outcomes were associated with fatigue symptoms. Subjects > 6 months showed smaller volumes in the putamen, pallidum, and thalamus compared to subjects < 6 months. In subjects > 6 months, fatigued subjects had smaller volumes in frontal areas compared to non-fatigued subjects. Moreover, worse fatigue was associated with smaller volumes in several frontal areas in subjects > 6 months.
The results revealed no brain metabolism differences between subjects > 6 and < 6 months. However, both groups exhibited both regional hypo- and hypermetabolism compared to a normative database. These results suggest that PCS may alter regional brain volumes but not metabolism in people > 6 months, particularly those experiencing fatigue symptoms.
Source: Deters JR, Fietsam AC, Gander PE, Boles Ponto LL, Rudroff T. Effect of Post-COVID-19 on Brain Volume and Glucose Metabolism: Influence of Time Since Infection and Fatigue Status. Brain Sciences. 2023; 13(4):675. https://doi.org/10.3390/brainsci13040675 https://www.mdpi.com/2076-3425/13/4/675 (Full text)

Long COVID: Cognitive and FDG PET evolutions in six patients

Abstract:

Long COVID is often characterized by cognitive complaints and deficits occurring immediately or several weeks after the infectious disease. Neuropsychological tests can revealed attention and executive function anomalies and FDG PET can display hypometabolic areas affecting various regions including frontal and cingulate cortices as well as precuneus and brainstem. We report here the cognitive and FDG PET evolutions over one year in 6 patients suffering from long COVID. Our study shows cognitive and FDG PET improvements in most of the cases and highlight the importance of a careful neurological follow-up in these patients.

Source: Jacques Hugon, Karim Farid, Mathieu Queneau et al. Long COVID: Cognitive and FDG PET evolutions in six patients, 03 April 2023, PREPRINT (Version 1) available at Research Square. https://doi.org/10.21203/rs.3.rs-2703691/v1 https://www.researchsquare.com/article/rs-2703691/v1 (Full text)

Brain 18F-FDG PET imaging in outpatients with post-COVID-19 conditions: findings and associations with clinical characteristics

Abstract:

Background: Brain 18F-FDG PET imaging has the potential to provide an objective assessment of brain involvement in post-COVID-19 conditions but previous studies of heterogeneous patient series yield inconsistent results. The current study aimed to investigate brain 18F-FDG PET findings in a homogeneous series of outpatients with post-COVID-19 conditions and to identify associations with clinical patient characteristics.

Methods: We retrospectively included 28 consecutive outpatients who presented with post-COVID-19 conditions between September 2020 and May 2022 and who satisfied the WHO definition, and had a brain 18F-FDG PET for suspected brain involvement but had not been hospitalized for COVID-19. A voxel-based group comparison with 28 age- and sex-matched healthy controls was performed (p-voxel at 0.005 uncorrected, p-cluster at 0.05 FWE corrected) and identified clusters were correlated with clinical characteristics.

Results: Outpatients with post-COVID-19 conditions exhibited diffuse hypometabolism predominantly involving right frontal and temporal lobes including the orbito-frontal cortex and internal temporal areas. Metabolism in these clusters was inversely correlated with the number of symptoms during the initial infection (r = – 0.44, p = 0.02) and with the duration of symptoms (r = – 0.39, p = 0.04). Asthenia and cardiovascular, digestive, and neurological disorders during the acute phase and asthenia and language disorders during the chronic phase (p ≤ 0.04) were associated with these hypometabolic clusters.

Conclusion: Outpatients with post-COVID-19 conditions exhibited extensive hypometabolic right fronto-temporal clusters. Patients with more numerous symptoms during the initial phase and with a longer duration of symptoms were at higher risk of persistent brain involvement.

Source: Goehringer F, Bruyere A, Doyen M, Bevilacqua S, Charmillon A, Heyer S, Verger A. Brain 18F-FDG PET imaging in outpatients with post-COVID-19 conditions: findings and associations with clinical characteristics. Eur J Nucl Med Mol Imaging. 2022 Nov 2. doi: 10.1007/s00259-022-06013-2. Epub ahead of print. PMID: 36322190. https://link.springer.com/article/10.1007/s00259-022-06013-2 (Full text)

Utility of positron emission tomography imaging in the diagnosis of chronic Q fever: A Systematic Review

Abstract:

Chronic Q fever is a diagnostic challenge. Diagnosis relies on serology and/or the detection of DNA from blood or tissue samples. PET-CT identifies tissues with increased glucose metabolism, thus identifying foci of inflammation. Our aim was to review the existing literature on the use of PET-CT to help diagnose chronic Q fever. A literature search was conducted in PubMed and Google Scholar to ascertain publications that included the terms ‘Positron Emission Tomography’ and ‘PET CT’ in combination with subheadings ‘chronic Q fever’ and ‘Coxiella burnetii’ within the search. To broaden our search retrieval, we used the terms ‘chronic Q fever’ and ‘PET-CT’.

Published literature up to 16th April 2020 was included. 274 articles were initially identified. Post-exclusion criteria, 46 articles were included. Amongst case reports and series, the most frequent focus of infection was vascular, followed by musculoskeletal then cardiac. 79.5% of patients had a focus detected with 55.3% of these having proven infected prosthetic devices. Amongst the retrospective and prospective studies, a total of 394 positive sites of foci were identified with 186 negative cases. Some had follow-up scans (53), with 75.5% showing improvement or resolution. Average timeframe for documented radiological resolution post-initiating treatment was 8.86 months.

PET-CT is a useful tool in the management of chronic Q fever. Knowledge of a precise focus enables for directed surgical management helping reduce microbial burden, preventing future complications. Radiological resolution of infection can give clinicians reassurance on whether antimicrobial therapy can be ceased earlier, potentially limiting side effects.

Source: Sivabalan P, Visvalingam R, Grey V, Blazak J, Henderson A, Norton R. Utility of positron emission tomography imaging in the diagnosis of chronic Q fever: A Systematic Review. J Med Imaging Radiat Oncol. 2021 May 30. doi: 10.1111/1754-9485.13244. Epub ahead of print. PMID: 34056851. https://pubmed.ncbi.nlm.nih.gov/34056851/

Brain Science on Myalgic Encephalomyelitis/Chronic Fatigue Syndrome

Abstract:

Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a disease characterized by chronic, profound, disabling, and unexplained fatigue. A variety of studies have been performed to establish objective biomarkers of the disease, including positron emission tomography (PET) molecular imaging and neuro-functional imaging using magnetic resonance imaging (MRI) and magnetoencephalogram (MEG). In this chapter, we summarize the results from PET, MRI, and MEG imaging.

Regional cerebral blood flow and glucose utilization rates are decreased in patients with ME/CFS as compared with age- and sex-matched healthy subjects. Acetyl-L-carnitine uptake into the releasable pool of glutamate and serotonin transporters densities are decreased in a few specific brain regions, mostly in the anterior cingulate in the patients. Although it is hypothesized that brain inflammation is involved in the pathophysiology of ME/CFS, there was no direct evidence of neuroinflammation in patients.

Our recent PET study successfully demonstrated that neuroinflammation is present in widespread brain areas in ME/CFS patients, and is associated with the severity of neuropsychological symptoms. Evaluation of neuroinflammation in patients with ME/CFS may be essential for understanding the core pathophysiology, as well as for developing objective diagnostic criteria and effective medical treatments for ME/CFS. By using specific neurological features of these patients such as prefrontal cortical atrophies and the over-guarding phenomenon were found using MRI and functional MRI, respectively. We here describe related pathophysiological findings and topics in order to aid in the development of future therapies for ME/CFS patients.

Source: Watanabe Y. Brain Science on Myalgic Encephalomyelitis/Chronic Fatigue Syndrome. Brain Nerve. 2018 Nov;70(11):1193-1201. doi: 10.11477/mf.1416201164. [Article in Japanese]  https://www.ncbi.nlm.nih.gov/pubmed/30416112

Neuroinflammation in the Brain of Patients with Myalgic Encephalomyelitis/Chronic Fatigue Syndrome

Abstract:

Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is characterized by chronic, profound, disabling, and unexplained fatigue; cognitive impairment; and chronic widespread pain. By using positron emission tomography, our study demonstrated neuroinflammation in the brain of patients with ME/CFS. Neuroinflammation was found to be widespread in the brain areas of the patients with ME/CFS and was associated with the severity of their neuropsychological symptoms. The ongoing research would lead to the establishment of objective diagnostic criteria and development of an appropriate therapy.

Source: Nakatomi Y1, Kuratsune H, Watanabe Y. Neuroinflammation in the Brain of Patients with Myalgic Encephalomyelitis/Chronic Fatigue Syndrome. Brain Nerve. 2018 Jan;70(1):19-25. doi: 10.11477/mf.1416200945. [Article in Japanese] https://www.ncbi.nlm.nih.gov/pubmed/29348371

Toward a clearer diagnosis of chronic fatigue syndrome

Researchers at the RIKEN Center for Life Science Technologies, in collaboration with Osaka City University and Kansai University of Welfare Sciences, have used functional PET imaging to show that levels of neuroinflammation, or inflammation of the nervous system, are higher in patients with chronic fatigue syndrome than in healthy people.

Chronic fatigue syndrome, which is also known as myalgic encephalomyelitis, is a debilitating condition characterized by chronic, profound, and disabling fatigue. Unfortunately, the causes are not well understood.

Neuroinflammation — the inflammation of nerve cells — has been hypothesized to be a cause of the condition, but no clear evidence has been put forth to support this idea. Now, in this clinically important study, published in The Journal of Nuclear Medicine, the researchers found that indeed the levels of neuroinflammation markers are elevated in CFS/ME patients compared to the healthy controls.

The researchers performed PET scanning on nine people diagnosed with CFS/ME and ten healthy people, and asked them to complete a questionnaire describing their levels of fatigue, cognitive impairment, pain, and depression. For the PET scan they used a protein that is expressed by microglia and astrocyte cells, which are known to be active in neuroinflammation.

The researchers found that neuroinflammation is higher in CFS/ME patients than in healthy people. They also found that inflammation in certain areas of the brain — the cingulate cortex, hippocampus, amygdala, thalamus, midbrain, and pons — was elevated in a way that correlated with the symptoms, so that for instance, patients who reported impaired cognition tended to demonstrate neuroinflammation in the amygdala, which is known to be involved in cognition. This provides clear evidence of the association between neuroinflammation and the symptoms experienced by patients with CFS/ME.

Though the study was a small one, confirmation of the concept that PET scanning could be used as an objective test for CFS/ME could lead to better diagnosis and ultimately to the development of new therapies to provide relief to the many people around the world afflicted by this condition.

Dr. Yasuyoshi Watanabe, who led the study at RIKEN, stated, “We plan to continue research following this exciting discovery in order to develop objective tests for CFS/ME and ultimately ways to cure and prevent this debilitating disease.”

Journal Reference: Y. Nakatomi, K. Mizuno, A. Ishii, Y. Wada, M. Tanaka, S. Tazawa, K. Onoe, S. Fukuda, J. Kawabe, K. Takahashi, Y. Kataoka, S. Shiomi, K. Yamaguti, M. Inaba, H. Kuratsune, Y. Watanabe. Neuroinflammation in Patients with Chronic Fatigue Syndrome/Myalgic Encephalomyelitis: An 11C-(R)-PK11195 PET Study. Journal of Nuclear Medicine, 2014; DOI:10.2967/jnumed.113.131045

 

Source: RIKEN. “Toward a clearer diagnosis of chronic fatigue syndrome.” ScienceDaily. ScienceDaily, 4 April 2014. https://www.sciencedaily.com/releases/2014/04/140404085538.htm

 

Neuroinflammation in Patients with Chronic Fatigue Syndrome/Myalgic Encephalomyelitis: An ¹¹C-(R)-PK11195 PET Study

Abstract:

Chronic fatigue syndrome/myalgic encephalomyelitis (CFS/ME) is a disease characterized by chronic, profound, disabling, and unexplained fatigue. Although it is hypothesized that brain inflammation is involved in the pathophysiology of CFS/ME, there is no direct evidence of neuroinflammation in patients with CFS/ME. Activation of microglia or astrocytes is related to neuroinflammation. (11)C-(R)-(2-chlorophenyl)-N-methyl-N-(1-methylpropyl)-3-isoquinoline-carboxamide ((11)C-(R)-PK11195) is a ligand of PET for a translocator protein that is expressed by activated microglia or astrocytes. We used (11)C-(R)-PK11195 and PET to investigate the existence of neuroinflammation in CFS/ME patients.

METHODS: Nine CFS/ME patients and 10 healthy controls underwent (11)C-(R)-PK11195 PET and completed questionnaires about fatigue, fatigue sensation, cognitive impairments, pain, and depression. To measure the density of translocator protein, nondisplaceable binding potential (BP(ND)) values were determined using linear graphical analysis with the cerebellum as a reference region.

RESULTS: The BP(ND) values of (11)C-(R)-PK11195 in the cingulate cortex, hippocampus, amygdala, thalamus, midbrain, and pons were 45%-199% higher in CFS/ME patients than in healthy controls. In CFS/ME patients, the BP(ND) values of (11)C-(R)-PK11195 in the amygdala, thalamus, and midbrain positively correlated with cognitive impairment score, the BP(ND) values in the cingulate cortex and thalamus positively correlated with pain score, and the BP(ND) value in the hippocampus positively correlated with depression score.

CONCLUSION: Neuroinflammation is present in widespread brain areas in CFS/ME patients and was associated with the severity of neuropsychologic symptoms. Evaluation of neuroinflammation in CFS/ME patients may be essential for understanding the core pathophysiology and for developing objective diagnostic criteria and effective medical treatments.

© 2014 by the Society of Nuclear Medicine and Molecular Imaging, Inc.

 

Source: Nakatomi Y, Mizuno K, Ishii A, Wada Y, Tanaka M, Tazawa S, Onoe K, Fukuda S, Kawabe J, Takahashi K, Kataoka Y, Shiomi S, Yamaguti K, Inaba M, Kuratsune H, Watanabe Y. Neuroinflammation in Patients with Chronic Fatigue Syndrome/Myalgic Encephalomyelitis: An ¹¹C-(R)-PK11195 PET Study. J Nucl Med. 2014 Jun;55(6):945-50. doi: 10.2967/jnumed.113.131045. Epub 2014 Mar 24. http://jnm.snmjournals.org/content/55/6/945.long (Full article)

 

Brain 5-HT1A receptor binding in chronic fatigue syndrome measured using positron emission tomography and [11C]WAY-100635

Abstract:

BACKGROUND: Research from neuroendocrine challenge and other indirect studies has suggested increased central 5-HT function in chronic fatigue syndrome (CFS) and increased 5-HT1A receptor sensitivity. We assessed brain 5-HT1A receptor binding potential directly using the specific radioligand [11C]WAY-100635 and positron emission tomography (PET).

METHODS: We selected 10 patients from a tertiary referral clinic who fulfilled the CDC consensus criteria for CFS. To assemble a homogenous group and avoid confounding effects, we enrolled only subjects who were completely medication-free and did not have current comorbid psychiatric illness. We also scanned 10 healthy control subjects.

RESULTS: There was a widespread reduction in 5-HT1A receptor binding potential in CFS relative to control subjects. This was particularly marked in the hippocampus bilaterally, where a 23% reduction was observed.

CONCLUSIONS: There is evidence of decreased 5-HT1A receptor number or affinity in CFS. This may be a primary feature of CFS, related to the underlying pathophysiology, or a finding secondary to other processes, such as previous depression, other biological changes or the behavioral consequences of CFS.

 

Source: Cleare AJ, Messa C, Rabiner EA, Grasby PM. Brain 5-HT1A receptor binding in chronic fatigue syndrome measured using positron emission tomography and [11C]WAY-100635. Biol Psychiatry. 2005 Feb 1;57(3):239-46. http://www.ncbi.nlm.nih.gov/pubmed/15691524